Abnormal Development of Blastocysts and Blastomeres in the Rhesus Monkey1

Abstract

Preimplantation stages were collected from normal rhesus monkeys by flushing of the uterine lumen. There was a high incidence of abnormal morulae and blastocysts (25%), as well as abnormal cells and cell death in otherwise normal blastocysts. In addition to cell and nuclear fragmentation, clustering of organelles in the center of the blastomeres was a common feature in early degeneration of ova and blastomeres. Large isolated cells that lagged in cytological development were found both in large numbers in an abnormal blastocyst and as individual cells in normal blastocysts. One apparently abnormal blastocyst was composed of normal trophoblast and inner cell mass cells, but lacked desmosomes and was collapsed. The cytological study of development of the blastocyst indicated that assessment of viability of primate blastocysts by light microscopic observation of morulae and blastocyst stages is probably more fraught with difficulty than might appear from studies of common laboratory animals.

Bovine abnormal preimplantation embryos: analysis of segregated cells occurring in the subzonal space and/or blastocoele cavity for their nuclear morphology and persistence of RNA synthesis

“…Dead or dying cells have been found in otherwise normal primate preimplantation-stage embryos produced in vivo (Enders et al, 1982). Thus, it appears that production of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 146 J.…”

Les régulateurs d’apoptose de la famille Bcl-2 dans les gamètes et lors du développement embryonnaire précoce

“…Elle résulte d'une cascade complexe d'événements régulés et coordonnés par l'interaction d'au moins 100 produits de gènes qui inhibent ou activent l'autodestruction de la cellule. Des phénomènes d'apoptose ont été décrits dans les embryons préimplantatoires de nombreuses espèces de mammifères y compris l'humain, à la fois in vitro et in vivo [2][3][4][5][6][7][8]. L'apoptose présente dans l'embryon préimplantatoire peut avoir des origines intrinsèques à l'embryon ou extrinsèques en relation avec l'environnement dans lequel il se développe, mais sa cause primaire pourrait également résulter d'une mauvaise qualité des gamètes (en particulier l'ovocyte).…”

Cytoplasmic fragmentation in activated eggs occurs in the cytokinetic phase of the cell cycle, in lieu of normal cytokinesis, and in response to cytoskeletal disorder

“…Both in vitro and in vivo, cleavage stage embryos of practically all mammalian species examined so far have been found often to comprise not only nucleated cells, but also non-nucleated cells, or 'fragments', of varying size and number (Edwards et al, 1970;Killeen and Moore, 1971;Enders et al, 1982;Buster et al, 1985). The fragments do not contribute directly to the development of the embryo proper, and therefore the most obvious and immediate result of fragmentation is that the embryo has a smaller than normal cytoplasmic volume and is deprived of any endogenous resources contained in the fragments.…”